1. Field of the Invention
The present invention relates to an image forming method and an image forming apparatus.
2. Description of the Related Art
An image forming apparatus using electrophotography, which is represented by the Carlson process, has been conventionally known. Such an image forming apparatus uniformly charges a photosensitive element having photoconductivity, and forms a latent image using exposing light corresponding to an image pattern as an electric charge distribution, and visualizes the latent image using resin coloring fine particles (hereinafter, referred to as toner) that are positively or negatively charged. The toner is then transferred onto the surface of a transfer medium such as a transfer sheet by an electrostatic force, and the transfer medium is passed between rollers to which a pressure is applied, to allow the image to be fixed onto the transfer medium due to the elasticity of the toner, and to achieve the final toner image.
As a method for fixing a toner image onto a transfer sheet, a method using thermal energy is widely practiced.
However, thermal fixing using thermal energy uses 60 percent or more of the power consumed by an image forming apparatus. Because the fixing has a large impact on energy saving, technologies such as that disclosed in “Denshi Shashin (Electrophography)”, Tokyo Denki University Press, pp. 78-96 have been developed to reduce energy consumption in the fixing.
Japanese Patent Application Laid-open No. 2010-191197 and Japanese Patent Application Laid-open No. 2010-204358 disclose an image forming apparatus in which a toner image is fixed onto a transfer sheet with a pressure. In the image forming apparatus disclosed in Japanese Patent Application Laid-open No. 2010-191197 and Japanese Patent Application Laid-open No. 2010-204358, a pressure is applied to a toner image on an intermediate transfer belt being an image carrier to transform the toner image into a film, and the film being the toner image is transferred onto the transfer sheet. Transforming a toner image into a film herein means a condition in which a toner image can be integrally removed from the intermediate transfer belt when the toner image on the intermediate transfer belt is lifted with a pair of tweezers. By transforming the toner image on the intermediate transfer belt into a film, toner scattering in transferring the toner image onto transfer sheet, or incomplete images, e.g., missing toner around a character, can be prevented.
However, in order to transform a toner image into a film in the manner disclosed in Japanese Patent Application Laid-open No. 2010-191197 and Japanese Patent Application Laid-open No. 2010-204358, toner particles making up the toner image need to be fused. Therefore, a large pressure needs to be applied to the toner image. As a result, the driving load of the intermediate transfer belt is increased, disadvantageously.
This problem is inherent in any structure that transforms a toner image on an image carrier into a film, without any limitations to an intermediate transfer belt.
The present invention is made in consideration of above, and an object of the present invention is to provide an image forming apparatus that can suppress toner scattering and incomplete images, and reduce driving load of an image carrier.